The use of hot melt adhesives has increased greatly over the past two decades. They are used in a variety of applications, including packaging, paper laminates, nonwoven fabric impregnation, bookbinding, furniture, label, and other operations. Hot melt adhesives are advantageous because they are substantially non-polluting as compared to organically based solvent-containing systems and they do not employ water as a solvent. Water is harmful to many substrates as it can promote corrosion of ferrous surfaces and can warp wooden surfaces.
Hot melt adhesives can be thermoplastic or thermoset. If thermoplastic, they are subject to softening upon re-exposure to heat. If they are based on thermoset resins, they may give off dangerous volatile organic compounds, such as phenol or methyl ethyl ketoxime, upon curing. Moreover, many of today's available thermosets are based on expensive ingredients, such as the polyurethanes and the polyacrylates.
It is an object to provide a cost effective hot melt thermoset adhesive that will cure rapidly to bond a variety of different substrates.
It is another object to provide a storage stable hot melt thermoset that can be stored and shipped without product deterioration.
Another object is to provide a thermoset hot melt adhesive that will not give off dangerous volatiles upon curing.